Introduction This article explains about how to validate an XML document with XSD schema.

However I've been having issues trying to perform XPath queries to select the data I wish to display in my XSLT.
When I use generic selectors like './/' or '*' I get the results I'd expect.
To send the validated output to Salesforce, add an action.
To test your validation action, make a request to the HTTP endpoint.
However when I try to use more specific selectors like : 'root/responses' or any other variant hereof, I get no results.
The XML file is validated correctly by the XSD, so I guess my data is at least somewhat correct.
It turns out there must have been a typo in the namespace reference.
After double checking this post: xslt-transform-xml-with-namespaces Which basically turns out to be the same question. ), I tried adding a namespace reference again, and this time it worked flawlessly!
Often in B2B scenarios, the partners in an agreement must make sure that the messages they exchange are valid before data processing can start.